Using Transform vs ImageFiltered to rotate widget

main.dart

import 'dart:math';
import 'dart:ui';

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> with SingleTickerProviderStateMixin {
  AnimationController _controller;
  bool _useFilter = false;
  bool _complexChild = false;
  GlobalKey _childKey = GlobalKey(debugLabel: 'child to rotate');
  Offset _childCenter = Offset.zero;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((timeStamp) {
      RenderBox childBox = _childKey.currentContext.findRenderObject();
      Offset localCenter = childBox.paintBounds.center;
      _childCenter = childBox.localToGlobal(localCenter);
    });
    _controller = AnimationController(vsync: this, duration: Duration(seconds: 2));
    _controller.repeat();
  }

  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }

  Widget makeChild(double w, double h) {
    if (_complexChild) {
      return Stack(
        children: <Widget>[
          for (int i = 0; i < 300; i++)
            Transform(
              transform: Matrix4.rotationZ(pi * 2.0 * i / 300.0),
              alignment: Alignment.center,
              child: Text('child',
                style: TextStyle(
                  color: HSVColor.fromAHSV(1.0, i * 360.0 / 300.0, 1.0, 1.0).toColor(),
                  fontSize: 36,
                ),
              ),
            ),
          Text('child',
            style: TextStyle(
              color: Colors.white,
              fontSize: 36,
            ),
          ),
        ],
      );
    } else {
      return Text('child',
        style: TextStyle(
          color: Colors.blue,
          fontSize: 36,
        ),
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: AnimatedBuilder(
          animation: _controller,
          builder: (context, child) {
            Matrix4 matrix = Matrix4.identity();
            if (_useFilter) matrix.translate(_childCenter.dx, _childCenter.dy);
            matrix.rotateZ(_controller.value * 2.0 * pi);
            if (_useFilter) matrix.translate(- _childCenter.dx, - _childCenter.dy);
            if (_useFilter) {
              return ImageFiltered(
                imageFilter: ImageFilter.matrix(matrix.storage),
                child: child,
              );
            } else {
              return Transform(
                transform: matrix,
                alignment: Alignment.center,
                child: child,
              );
            }
          },
          child: RepaintBoundary(
            child: Container(
              key: _childKey,
              color: Colors.yellow,
              width: 300,
              height: 300,
              child: Center(
                child: makeChild(300, 300),
              ),
            ),
          ),
        ),
      ),
      bottomNavigationBar: BottomAppBar(
        child: Row(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text('Use ImageFiltered:'),
            Checkbox(
              value: _useFilter,
              onChanged: (b) => setState(() => _useFilter = b),
            ),
            Text('Complex child:'),
            Checkbox(
              value: _complexChild,
              onChanged: (b) => setState(() => _complexChild = b),
            ),
          ],
        ),
      ),
    );
  }
}